Hello,

What type of PID function you are using?First of all check all your floating point inputs fed into PID function(DB3,DBD48 and DB3,DBD44).Validity check can be done by 2 comparisong and a MOVE for substitute value generation.

I hope this helps,

hdhosseini

QNAN stands for quiet "not a number".

see http://en.wikipedia.org/wiki/NaN

Not a number is the floating point exception error that is a result of a floating point operation that is either illegal (i.e. division by zero) or which the result is indeterminate (e.g. 0 / 0). The quiet bit means that is a "soft" error which will not propagte trough the entire real number calculation trail.

So you have a value or values that are being used in a floating point calculation that has resulted in a floating point exception. The most likely cause is a division operation. Check your divisors.